Universal Access To All Knowledge
Home Donate | Store | Blog | FAQ | Jobs | Volunteer Positions | Contact | Bios | Forums | Projects | Terms, Privacy, & Copyright
Search: Advanced Search
Anonymous User (login or join us)
Upload
Search Results
Results: 1 through 50 of 782,675 (1.31 secs)
You searched for: (collection:arxiv OR mediatype:arxiv) AND -mediatype:collection
[1] 2 3 4 5 6 7 8 9 10 11     Next    Last
[texts]Compositions and Fibonacci Identities - Ira M. Gessel
We study formulas expressing Fibonacci numbers as sums over compositions using free submonoids of the free monoid of compositions with parts 1 and 2.
Downloads: 32
[texts]Une identité remarquable en théorie des partitions - Alain Lascoux
We prove an identity about partitions, previously conjectured in the study of shifted Jack polynomials (math.CO/9903020). The proof given is using $\lambda$-ring techniques. It would be interesting to obtain a bijective proof.
Downloads: 16
[texts]Pre-big bang in M-theory - Marco Cavaglia
We discuss a simple cosmological model derived from M-theory. Three assumptions lead naturally to a pre-big bang scenario: (a) 11-dimensional supergravity describes the low-energy world; (b) non-gravitational fields live on a three-dimensional brane; and (c) asymptotically past triviality.
Downloads: 206
[texts]Forbidden transitions in the helium atom - Grzegorz Lach
Nonrelativistically forbidden, single-photon transition rates between low lying states of the helium atom are rigorously derived within quantum electrodynamics theory. Equivalence of velocity and length gauges, including relativistic corrections is explicitly demonstrated. Numerical calculations of matrix elements are performed with the use of high precision variational wave functions and compared to former results.
Downloads: 34
[texts]"Divergent" Ramanujan-type supercongruences - Jesús Guillera
"Divergent" Ramanujan-type series for $1/\pi$ and $1/\pi^2$ provide us with new nice examples of supercongruences of the same kind as those related to the convergent cases. In this paper we manage to prove three of the supercongruences by means of the Wilf--Zeilberger algorithmic technique.
Downloads: 65
[texts]Ludwig Boltzmann -- A Pioneer of Modern Physics - D. Flamm
In two respects Ludwig Boltzmann was a pioneer of quantum mechanics. First because in his statistical interpretation of the second law of thermodynamics he introduced the theory of probability into a fundamental law of physics and thus broke with the classical prejudice, that fundamental laws have to be strictly deterministic. Even Max Planck had not been ready to accept Boltzmann's statistical methods until 1900...
Downloads: 41
[texts]Ranking-Based Black-Box Complexity - Benjamin Doerr
Randomized search heuristics such as evolutionary algorithms, simulated annealing, and ant colony optimization are a broadly used class of general-purpose algorithms. Analyzing them via classical methods of theoretical computer science is a growing field. While several strong runtime analysis results have appeared in the last 20 years, a powerful complexity theory for such algorithms is yet to be developed...
Downloads: 12
[texts]Automatic Methods for Analyzing Non-Repudiation Protocols with an Active Intruder - Francis Klay
Non-repudiation protocols have an important role in many areas where secured transactions with proofs of participation are necessary. Formal methods are clever and without error, therefore using them for verifying such protocols is crucial. In this purpose, we show how to partially represent non-repudiation as a combination of authentications on the Fair Zhou-Gollmann protocol. After discussing its limits, we define a new method based on the handling of the knowledge of protocol participants...
Downloads: 13
[texts]Instabilities in crystal growth by atomic or molecular beams - Paolo Politi
The planar front of a growing a crystal is often destroyed by instabilities. In the case of growth from a condensed phase, the most frequent ones are diffusion instabilities, which will be but briefly discussed in simple terms in chapter II. The present review is mainly devoted to instabilities which arise in ballistic growth, especially Molecular Beam Epitaxy (MBE). The reasons of the instabilities can be geometric (shadowing effect), but they are mostly kinetic or thermodynamic...
Downloads: 15
[texts]The HD 163296 Circumstellar Disk in Scattered Light: Evidence of Time-Variable Self-Shadowing - John P. Wisniewski
We present the first multi-color view of the scattered light disk of the Herbig Ae star HD 163296, based on coronagraphic observations from the Hubble Space Telescope Advanced Camera for Surveys (ACS). Radial profile fits of the surface brightness along the disk's semi-major axis indicates that the disk is not continuously flared, and extends to 540 AU. The disk's color (V-I)=1.1 at a radial distance of 3.5 arcseconds is redder than the observed stellar color (V-I)=0.15...
Downloads: 13
[texts]Quantum Brain? - A. Mershin
In order to create a novel model of memory and brain function, we focus our approach on the sub-molecular (electron), molecular (tubulin) and macromolecular (microtubule) components of the neural cytoskeleton. Due to their size and geometry, these systems may be approached using the principles of quantum physics. We identify quantum-physics derived mechanisms conceivably underlying the integrated yet differentiated aspects of memory encoding/recall as well as the molecular basis of the engram...
Downloads: 21
[texts]Another look at the Pioneer anomaly - Erhard Scholz
The often quoted equ. (15) in (Anderson_ea:2002) defines the observed Pioneer anomaly $a_P$ such that literal reading suggests $\nu_{obs} \nu_{mod}$. Version 1 to 4 of this paper built upon the first reading and led to a correction term for frequency shifts of wrong sign. Thus the proposal therein does not resolve the Pioneer anomaly, although it gives a correction term for frequencies which has the correct absolute value.
Downloads: 43
[texts]A proposal that explains the Pioneer anomaly - Antonio F. Ranada
We propose here an explanation of the Pioneer anomaly which is not in conflict with the cartography of the solar system. In our model, the spaceship does not suffer any extra acceleration but follows the trajectory predicted by standard gravitational theory. The observed acceleration is not real but apparent and has the same observational footprint as a deceleration of astronomical time with respect to atomic time...
Downloads: 182
[texts]Curious numerical coincidence to the Pioneer anomaly - Liviu Ivanescu
One noticed a pure numerical coincidence between the Pioneer spacecrafts deceleration anomaly and (gamma-1), with gamma the Lorentz factor. The match is not only for distances larger than 20 AU, but even for the observed slop between 10 and 20 AU.
Downloads: 129
[texts]Covering n-Permutations with (n+1)-Permutations - Taylor Allison
Let S_n be the set of all permutations on [n]:={1,2,....,n}. We denote by kappa_n the smallest cardinality of a subset A of S_{n+1} that "covers" S_n, in the sense that each pi in S_n may be found as an order-isomorphic subsequence of some pi' in A. What are general upper bounds on kappa_n? If we randomly select nu_n elements of S_{n+1}, when does the probability that they cover S_n transition from 0 to 1? Can we provide a fine-magnification analysis that provides the "probability of coverage" w...
Downloads: 10
[texts]Overlapping Probabilities of Top Ranking Gene Lists, Hypergeometric Distribution, and Stringency of Gene Selection Criterion - Wen Fury
When the same set of genes appear in two top ranking gene lists in two different studies, it is often of interest to estimate the probability for this being a chance event. This overlapping probability is well known to follow the hypergeometric distribution. Usually, the lengths of top-ranking gene lists are assumed to be fixed, by using a pre-set criterion on, e.g., $p$-value for the t-test. We investigate how overlapping probability changes with the gene selection criterion, or simply, with th...
Downloads: 14
[texts]Discrete analogue computing with rotor-routers - James Propp
Rotor-routing is a procedure for routing tokens through a network that can implement certain kinds of computation. These computations are inherently asynchronous (the order in which tokens are routed makes no difference) and distributed (information is spread throughout the system). It is also possible to efficiently check that a computation has been carried out correctly in less time than the computation itself required, provided one has a certificate that can itself be computed by the rotor-ro...
Downloads: 316
[texts]Software Infrastructure for Natural Language Processing - Hamish Cunningham
We classify and review current approaches to software infrastructure for research, development and delivery of NLP systems. The task is motivated by a discussion of current trends in the field of NLP and Language Engineering. We describe a system called GATE (a General Architecture for Text Engineering) that provides a software infrastructure on top of which heterogeneous NLP processing modules may be evaluated and refined individually, or may be combined into larger application systems...
Downloads: 89
[texts]Big Bang Nucleosynthesis - Keith A. Olive
The concordance of standard big bang nucleosynthesis theory and the related observations of the light element isotopes (including some new higher \he4 abundances) will be reviewed. Implications of BBN on chemical evolution, dark matter and constraints on particle properties will be discussed.
Downloads: 307
[texts]Robust Estimation of Operational Risk - Nataliya Horbenko
According to the Loss Distribution Approach, the operational risk of a bank is determined as 99.9% quantile of the respective loss distribution, covering unexpected severe events. The 99.9% quantile can be considered a tail event. As supported by the Pickands-Balkema-de Haan Theorem, tail events exceeding some high threshold are usually modeled by a Generalized Pareto Distribution (GPD). Estimation of GPD tail quantiles is not a trivial task, in particular if one takes into account the heavy tai...
Downloads: 40
[texts]Controllable valley splitting in silicon quantum devices - Srijit Goswami
Silicon has many attractive properties for quantum computing, and the quantum dot architecture is appealing because of its controllability and scalability. However, the multiple valleys in the silicon conduction band are potentially a serious source of decoherence for spin-based quantum dot qubits. Only when these valleys are split by a large energy does one obtain well-defined and long-lived spin states appropriate for quantum computing...
Downloads: 16
[texts]About Time - M. D. Maia
The concept of time is discussed in the context of the canonical formulation of the gravitational field. Using a hypersurface orthogonal foliation, the arbitrariness of the lapse function is eliminated and the shift vector vanishes, allowing a consistent definition of time.
Downloads: 286
[texts]Hedging strategies with a put option and their failure rates - Guanghui Huang
The problem of stock hedging is reconsidered in this paper, where a put option is chosen from a set of available put options to hedge the market risk of a stock. A formula is proposed to determine the probability that the potential loss exceeds a predetermined level of Value-at-Risk, which is used to find the optimal strike price and optimal hedge ratio. The assumptions that the chosen put option finishes in-the-money and the constraint of hedging budget is binding are relaxed in this paper...
Downloads: 189
[texts]An Empirical Investigation of the Forward Interest Rate Term Structure - Andrew Matacz
In this paper we study empirically the Forward Rate Curve (FRC) of 5 different currencies. We confirm and extend the findings of our previous investigation of the U.S. Forward Rate Curve. In particular, the average FRC follows a square-root law, with a prefactor related to the spot volatility, suggesting a Value-at-Risk like pricing. We find a striking correlation between the instantaneous FRC and the past spot trend over a certain time horizon, in agreement with the idea of an extrapolated tren...
Downloads: 136
[texts]Coherent States and Squeezed States, Supercoherent States and Supersqueezed States - Michael Martin Nieto
This article reports on a program to obtain and understand coherent states for general systems. Most recently this has included supersymmetric systems. A byproduct of this work has been studies of squeezed and supersqueezed states. To obtain a physical understanding of these systems has always been a primary goal. In particular, in the work on supersymmetry an attempt to understand the role of Grassmann numbers in quantum mechanics has been initiated.
Downloads: 18
[texts]Hybrid states - Yu. S. Kalashnikova
Theoretical arguments are given in favour of existence of gluonic degrees of freedom at the constituent level. Models for hybrid mesons are discussed, and the predictions are compared with the data on meson spectroscopy in the light quark sector. It is demonstrated that the $q\bar q g$ content might be responsible for the properties of some recently found mesonic states.
Downloads: 17
[texts]Hyperentangled States - Rob Clifton
We investigate a new class of entangled states, which we call 'hyperentangled',that have EPR correlations identical to those in the vacuum state of a relativistic quantum field. We show that whenever hyperentangled states exist in any quantum theory, they are dense in its state space. We also give prescriptions for constructing hyperentangled states that involve an arbitrarily large collection of systems.
Downloads: 16
[texts]RESLVE: Leveraging User Interest to Improve Entity Disambiguation on Short Text - Elizabeth L. Murnane
We address the Named Entity Disambiguation (NED) problem for short, user-generated texts on the social Web. In such settings, the lack of linguistic features and sparse lexical context result in a high degree of ambiguity and sharp performance drops of nearly 50% in the accuracy of conventional NED systems. We handle these challenges by developing a model of user-interest with respect to a personal knowledge context; and Wikipedia, a particularly well-established and reliable knowledge base, is ...
Downloads: 14
[texts]Choosing a penalty for model selection in heteroscedastic regression - Sylvain Arlot
We consider the problem of choosing between several models in least-squares regression with heteroscedastic data. We prove that any penalization procedure is suboptimal when the penalty is a function of the dimension of the model, at least for some typical heteroscedastic model selection problems. In particular, Mallows' Cp is suboptimal in this framework. On the contrary, optimal model selection is possible with data-driven penalties such as resampling or $V$-fold penalties...
Downloads: 11
[texts]MediaWiki Grammar Recovery - Vadim Zaytsev
The paper describes in detail the recovery effort of one of the official MediaWiki grammars. Over two hundred grammar transformation steps are reported and annotated, leading to delivery of a level 2 grammar, semi-automatically extracted from a community created semi-formal text using at least five different syntactic notations, several non-enforced naming conventions, multiple misspellings, obsolete parsing technology idiosyncrasies and other problems commonly encountered in grammars that were ...
Downloads: 24
[texts]Main Sequence Masses and Radii from Gravitational Redshifts - Ted von Hippel
Modern instrumentation makes it possible to measure the mass to radius ratio for main sequence stars in open clusters from gravitational redshifts. For stars where independent information is available for either the mass or the radius, this application of general relativity directly determines the other quantity. Applicable examples are: 1) measuring the radii of solar metallicity main sequence stars for which the mass - luminosity relation is well known, 2) measuring the radii for stars where m...
Downloads: 13
[texts]Lyman-alpha Cooling Emission from Galaxy Formation - C. -A. Faucher-Giguere
Recent studies have shown that galaxies accrete most of their baryons via the cold mode, from streams with temperatures T~10^4-10^5 K. At these temperatures, the streams should radiate primarily in the Lya line and have therefore been proposed as a model to power the extended, high-redshift objects known as Lya blobs and other high-redshift Lya sources. We introduce a new Lya radiative transfer code, aRT, and apply it to cosmological hydrodynamical simulations...
Downloads: 14
[texts]Unimodularity and preservation of volumes in nonholonomic mechanics - Yuri N. Fedorov
The equations of motion of a mechanical system subjected to nonholonomic linear constraints can be formulated in terms of a linear almost Poisson structure in a vector bundle. We study the existence of invariant measures for the system in terms of the unimodularity of this structure. In the presence of symmetries, our approach allows us to give necessary and sufficient conditions for the existence of an invariant volume, that unify and improve results existing in the literature...
Downloads: 18
[texts]Valley blockade quantum switching in Silicon nanostructures - Enrico Prati
In analogy to the Coulomb and the Pauli spin blockade, based on the electrostatic repulsion and the Pauli exclusion principle respectively, the concept of valley blockade in Silicon nanostructures is explored. The valley parity operator is defined. Valley blockade is determined by the parity conservation of valley composition eigenvectors in quantum transport. A Silicon quantum changeover switch based on a triple of donor quantum dots capable to separate electrons having opposite valley parity b...
Downloads: 17
[texts]Big Bang Nucleosynthesis - Keith A. Olive
A brief review of standard big bang nucleosynthesis theory and the related observations of the light element isotopes is presented. Implications of BBN on chemical evolution and constraints on particle properties will also be discussed.
Downloads: 64
[texts]Coherent States - Peter W. Milonni
We concisely review the history, physics and significance of coherent states.
Downloads: 17
[texts]Su(2) intelligent states as coupled su(2) coherent states - Benjamin R. Lavoie
We show how su(2) intelligent states can be obtained by coupling su(2) coherent states. The construction is simple and efficient, and easily leads to a discussion of some general properties of su(2) intelligent states.
Downloads: 17
[texts]The benefits of the orthogonal LSM models - Z. Mikulasek
In the last few decades both the volume of high-quality observing data on variable stars and common access to them have boomed; however the standard used methods of data processing and interpretation have lagged behind this progress. The most popular method of data treatment remains for many decades Linear Regression (LR) based on the principles of Least Squares Method (LSM) or linearized LSM. Unfortunately, we have to state that the method of linear regression is not as a rule used accordingly ...
Downloads: 305
[texts]Classical Group Field Theory - Joseph Ben Geloun
The ordinary formalism for classical field theory is applied to dynamical group field theories. Focusing first on a local group field theory over one copy of SU(2) and, then, on more involved nonlocal theories (colored and non colored) defined over a tensor product of the same group, we address the issue of translation and dilatation symmetries and the corresponding Noether theorem. The energy momentum tensor and dilatation current are derived and their properties identified for each case.
Downloads: 19
[texts]Duality of Quasilocal Black Hole Thermodynamics - Jeongwon Ho
We consider T-duality of the quasilocal black hole thermodynamics for the three-dimensional low energy effective string theory. Quasilocal thermodynamic variables in the first law are explicitly calculated on a general axisymmetric three-dimensional black hole solution and corresponding dual one. Physical meaning of the dual invariance of the black hole entropy is considered in terms of the Euclidean path integral formulation.
Downloads: 12
[texts]Successive Superalgebraic Truncations from the Four-Dimensional Maximal Supergravity - Chang-Ho Kim
We study the four-dimensional {\it N}=8 maximal supergravity in the context of Lie superalgebra SU(8/1). All possible successive superalgebraic truncations from four-dimensional {\it N}=8 theory to {\it N}=7, 6, $\cdots$, 1 supergravity theories are systematically realized as sub-superalgebra chains of SU(8/1) by using the Kac-Dynkin weight techniques.
Downloads: 10
[texts]Progressive suppression of spin relaxation in 2D channels of finite width - A. A. Kiselev
We have investigated spatio-temporal kinetics of electron spin polarization in semiconductor narrow 2D strip and explored the ability to manipulate spin relaxation. Information about spin of the conduction electrons and mechanisms of spin rotation is incorporated into transport Monte Carlo simulation program. A model problem, involving linear-in-k splitting of the conduction band, responsible for the D'yakonov-Perel' mechanism of spin relaxation in the zinc-blende semiconductors and heterostruct...
Downloads: 16
[texts]Network Formation: Heterogeneous Traffic, Bilateral Contracting and Myopic Dynamics - Carme Àlvarez
We study a network formation game where nodes wish to send traffic to other nodes. Nodes can contract bilaterally other nodes to form bidirectional links as well as nodes can break unilaterally contracts to eliminate the corresponding links. Our model is an extension of the model considered in Arcaute et al. The novelty is that we do no require the traffic to be uniform all-to-all. Each node specifies the amount of traffic that it wants to send to any other node...
Downloads: 13
[texts]On Pure and (approximate) Strong Equilibria of Facility Location Games - Thomas Dueholm Hansen
We study social cost losses in Facility Location games, where $n$ selfish agents install facilities over a network and connect to them, so as to forward their local demand (expressed by a non-negative weight per agent). Agents using the same facility share fairly its installation cost, but every agent pays individually a (weighted) connection cost to the chosen location. We study the Price of Stability (PoS) of pure Nash equilibria and the Price of Anarchy of strong equilibria (SPoA), that gener...
Downloads: 5
[texts]Robust Distributed Estimation over Multiple Access Channels with Constant Modulus Signaling - Cihan Tepedelenlioglu
A distributed estimation scheme where the sensors transmit with constant modulus signals over a multiple access channel is considered. The proposed estimator is shown to be strongly consistent for any sensing noise distribution in the i.i.d. case both for a per-sensor power constraint, and a total power constraint. When the distributions of the sensing noise are not identical, a bound on the variances is shown to establish strong consistency...
Downloads: 6
[texts]An insight on the Proof of Orientifold Planar Equivalence on the Lattice - Agostino Patella
In a recent paper, Armoni, Shifman and Veneziano (ASV) gave a formal non-perturbative proof of planar equivalence between the bosonic sectors of SU(N) super Yang-Mills theory and of a gauge theory with a massless quark in the antisymmetric two-indexes representation. In the case of three colors, the latter theory is nothing but one-flavor QCD. Numerical simulations are necessary to test the validity of that proof and to estimate the size of 1/N corrections...
Downloads: 6
[texts]Isoscaling behavior in the Isospin dependent Quantum Molecular Dynamics model - W. D. Tian
The isoscaling behavior is investigated in the frame of Isospin dependent Quantum Molecular Dynamics (IQMD) models. The isotopic yields ratio $Y_2$/$Y_1$ for reactions $^{48}Ca$+$^{48}Ca$ and $^{40}Ca+^{40}Ca$ at different entrance channels are simulated and presented, the relationship between the isoscaling parameter and the entrance channel is analyzed, the results show that $\alpha$ and $\beta$ reduce with the rise of incident energies and increase with the impact parameter b, which can be at...
Downloads: 8
[texts]The reconstructed final state of Au + Au collisions from PHENIX and STAR data at sqrt{s}=130 AGeV - indication for quark deconfinement at RHIC - T. Csorgo
The final state of Au + Au collisions at sqrt{s}=130 AGeV at RHIC has been reconstructed within the framework of the Buda-Lund hydrodynamical model, by performing a simultaneous fit to final data on two-particle Bose-Einstein correlations of the STAR and PHENIX Collaborations, and final identified single particle spectra as measured by the PHENIX Collaboration. The results indicate a strongly three-dimensional expansion with a four-velocity field that is almost a spherically symmetric Hubble flo...
Downloads: 9
[texts]Structures in surface-brightness profiles of LMC and SMC star clusters: evidence of mergers? - Luziane Carvalho
The LMC and SMC are rich in binary star clusters, and some mergers are expected. It is important to characterize single clusters, binary clusters and candidates to mergers. We selected a sample of star clusters in each Cloud with this aim. Surface photometry of 25 SMC and 22 LMC star clusters was carried with the ESO Danish 1.54 m telescope. 23 clusters were observed for the first time for these purposes...
Downloads: 24
[texts]Another Hanukkah Miracle: The Gaps Between Consecutive Christmas-in-Hanukkah Years is ALWAYS a Fibonacci Number! - Shalosh B. Ekhad
The Hebrew Calendar is based on very deep and complicated mathematics, involving diophantine approximation, but it is very surprising that the gaps between consecutive Christmas-in-Hanukkah years is always a member of the set {2,3,5,8}.
Downloads: 6
[1] 2 3 4 5 6 7 8 9 10 11     Next    Last
Advanced search

Group results by:

> Relevance
Mediatype
Collection

Related mediatypes

texts